A lightweight underwater submersible composite sandwich load-bearing structure shell and its integrated molding process

Abstract

The present invention relates to the technical field of underwater submersibles, and specifically to a lightweight underwater submersible composite material sandwich load-bearing structure shell and an integrated molding process; wherein the lightweight underwater submersible composite material sandwich load-bearing structure shell comprises: a first skin and a pressure-resistant buoyancy layer, and a second skin laid in sequence, the first skin comprising a first surface aging-resistant layer and a first surface short fiber layer, and a first surface structural layer; grooves are provided on the upper and lower surfaces of the pressure-resistant buoyancy layer, and slots are provided along the thickness direction of the pressure-resistant buoyancy layer, and the slots in the grooves are filled with adhesive resin. The lightweight underwater submersible composite material sandwich load-bearing structure shell is light in weight and has good overall structural load-bearing performance; it is integrally and one-time molded using a vacuum-assisted resin transfer molding process, ensuring the reliability of the bonding between the materials in each layer and the uniformity and consistency of the thickness.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater submersibles, and in particular to a lightweight underwater submersible composite material sandwich load-bearing structure shell and an integrated molding process. Background Art

[0002] Currently, the practical needs of deep-sea resource exploration and military operations are placing higher demands on the performance of underwater submersibles. The submersible's load-bearing hull, which serves as a carrier for equipment, reduces drag and guides flow, and supports lifting, places particularly stringent demands on lightweighting. The requirement is to minimize weight while ensuring the performance of the load-bearing hull. This places higher demands on the product's structural design and molding process, requiring the process to achieve this within the thickness specified in the structural design.

[0003] The product is designed as a lightweight load-bearing shell with a sandwich structure composed of an epoxy resin-based carbon fiber reinforced composite material skin and an epoxy resin-based glass microsphere buoyancy material core. The theoretical weight and structural performance meet the required specifications. However, during the manufacturing process, due to the complex shape and structure of the product, the skin and core layers often need to be formed in multiple stages using the traditional hand lay-up process. This process is affected by uneven manual glue application, resulting in uneven skin wall thickness. The manual and multiple molding processes lead to significant quality issues in the finished product, such as bubbles and delamination at the bonding interface between the skin and core layers. These issues not only affect the performance of the load-bearing shell, but also significantly affect the buoyancy of the submersible under the high water pressure of the deep sea due to bubbles and water infiltration in the layers. Products of this type manufactured using traditional molding processes no longer meet the performance specifications and usage requirements, posing a significant safety risk to deep-sea submersibles. This technical bottleneck must be resolved before this lightweight structural design can be implemented in products. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the bracket in the existing technology cannot meet the complex and changeable air temperature measurement point position requirements of the test and has poor versatility, thereby providing a lightweight underwater submersible composite sandwich load-bearing structure shell and an integrated molding process.

[0005] In order to solve the above technical problems, the present invention provides a lightweight underwater submersible composite sandwich load-bearing structural shell, comprising: a first skin and a pressure-resistant buoyancy layer, and a second skin laid in sequence, the first skin comprising a first surface aging-resistant layer, a first surface short fiber layer, and a first surface structural layer; the second skin comprising a second surface aging-resistant layer, a second surface short fiber layer, and a second surface structural layer, the first surface structural layer and the second surface structural layer being close to the pressure-resistant buoyancy layer; grooves are provided on the upper and lower surfaces of the pressure-resistant buoyancy layer, and slots are provided along the thickness direction of the pressure-resistant buoyancy layer, and the slots in the grooves are filled with adhesive resin.

[0006] Furthermore, the channel includes a transverse groove body and a longitudinal groove body, and the transverse groove body and the longitudinal groove body are cross-arranged.

[0007] Furthermore, the thickness of the first surface aging-resistant layer and the first surface short fiber layer, the second surface aging-resistant layer, and the second surface short fiber layer is 0.15-0.2 mm.

[0008] Furthermore, the first surface aging-resistant layer and the second surface short fiber layer are composed of epoxy resin gel coat and 2% (mass fraction) fumed silica.

[0009] Furthermore, the first surface structural layer and the second surface structural layer are resin-based reinforced fiber reinforced composite material laminates.

[0010] Furthermore, the resin-based reinforced fiber reinforced composite material laminate comprises multiple layers of carbon fiber multi-axial cloth, and two adjacent layers of the carbon fiber multi-axial cloth are arranged perpendicular to each other.

[0011] Furthermore, the multiple layers of the carbon fiber multi-axial cloth are laid along 0° and 90° staggered seams respectively.

[0012] Furthermore, the multiple layers of the carbon fiber multi-axial cloth are laid along a ±45° staggered seam.

[0013] Furthermore, the thickness of each layer of the carbon fiber twill fabric is 0.2 to 0.6 mm.

[0014] The present invention also provides an integrated molding process for a lightweight underwater submersible composite sandwich load-bearing structural shell, comprising the following steps: S1, providing a mold that meets the requirements according to the shape and structure of the load-bearing structural shell, the mold being provided with a plurality of bonding resin injection ports and vacuum negative pressure interfaces; S2, using a wool roller to roll-coat a layer of epoxy resin gel coat and 2% (mass fraction) of gas-phase silica on the mold, and forming a first surface aging-resistant layer, which is cured at room temperature after the rolling is completed, and the thickness of the composite material layer is 0.1 to 0.15 mm; S3, evenly spraying an appropriate amount of fiber fixing glue on the cured first surface aging-resistant layer, and laying a first surface short fiber layer, and then laying the first surface structural layer on the first surface short fiber layer, the first layer of carbon fiber multi-axial cloth of the first surface short fiber layer is laid in a direction consistent with the axial direction of the load-bearing structural shell, and each width of carbon fiber multi-axial cloth is butt-laid, and when the carbon fiber multi-axial cloth covers the entire mold surface, spraying an appropriate amount of fiber fixing glue on the first layer of carbon fiber multi-axial cloth. , lay the second layer of carbon fiber multi-axial cloth along the 45° direction of the seam with the first layer of carbon fiber multi-axial cloth, and then lay the remaining -45° and 90° carbon fiber multi-axial cloths in this way; S4, the pressure-resistant buoyancy layer is a whole made of multiple pieces spliced ​​together. When laying, control the splicing gap, the gap is required to be less than 0.5mm, and align the grooves on the upper and lower surfaces of each pressure-resistant buoyancy layer one by one; S5, the second surface structure layer is laid on the pressure-resistant buoyancy layer, and the first layer of carbon fiber multi-axial cloth of the second surface structure is laid on the pressure-resistant buoyancy layer in a direction consistent with the axial direction of the load-bearing structure shell, and each width of carbon fiber multi-axial cloth is butt-laid. When the carbon fiber multi-axial cloth is laid, the pressure-resistant buoyancy layer is aligned with the pressure-resistant buoyancy layer. After the cloth is spread over the entire mold surface, spray an appropriate amount of fiber fixing glue on the first layer of carbon fiber multi-axial cloth, lay the second layer of carbon fiber multi-axial cloth along the 45° direction of the seam with the first layer of carbon fiber multi-axial cloth, and then lay the remaining -45° and 90° carbon fiber multi-axial cloths in this way; S6, evenly spray an appropriate amount of fiber fixing glue on the second surface structure, and lay the second short fiber layer, use a wool roller to roll a layer of epoxy resin gel coat and 2% (mass fraction) fumed silica on the second short fiber layer, and form a second surface aging resistant layer. After the roll coating is completed, wait for room temperature curing. The thickness of the composite material layer is 0.1 to 0.15 mm; S7, after the first coating is completed, Auxiliary material layers are sequentially laid on the leather surface, including a release layer, a first air guide layer, an adhesive resin flow channel, a first layer of sealing bag film, a second air guide layer, and a second layer of sealing bag film. In step S8, epoxy resin and a curing agent are mixed and stirred to form an adhesive resin. The adhesive resin has a gel time of 4 to 6 hours and a viscosity of 0.15 to 0.25 Pa·s. A pipe connected to the adhesive resin flow channel of the mold is connected to the adhesive resin injection port, and a vacuum negative pressure pipe is connected to the adhesive resin discharge port of the mold. The vacuum pressure in the first layer of sealing bag film must reach -0.07 MPa to -0.08 MPa, and the vacuum pressure in the second layer of sealing bag film must reach -0.0.9MPa to -0.1MPa, the bonding resin is introduced into the mold cavity under the action of the positive pressure of the injection equipment and the negative vacuum pressure. The bonding resin first flows through the auxiliary material layer. After the auxiliary material layer is saturated with the bonding resin, the second skin is also saturated. The bonding resin then flows into the first skin through the grooves of the pressure-resistant buoyancy layer and the slots within the pressure-resistant buoyancy layer, gradually saturating the first skin. When bonding resin overflows from each bonding resin outlet, indicating that the bonding resin has completely impregnated the auxiliary material layer, the second skin, the pressure-resistant buoyancy layer, and the first skin, the bonding resin injection can be stopped. However, the vacuum pressure at the negative vacuum pressure end must be maintained until the bonding is completely cured, and then the negative vacuum pressure is released. S9, the load-bearing structure shell is heated and cured in the mold.

[0015] The technical solution of the present invention has the following advantages:

[0016] 1. The lightweight underwater submersible composite sandwich load-bearing structural shell provided by the present invention includes: a first skin and a pressure-resistant buoyancy layer, and a second skin laid in sequence, the first skin including a first surface aging-resistant layer, a first surface short fiber layer, and a first surface structural layer; the second skin including a second surface aging-resistant layer, a second surface short fiber layer, and a second surface structural layer, the first surface structural layer and the second surface structural layer are close to the pressure-resistant buoyancy layer; grooves are provided on the upper and lower surfaces of the pressure-resistant buoyancy layer, and slots are provided along the thickness direction of the pressure-resistant buoyancy layer, and the slots in the grooves are filled with adhesive resin.

[0017] The first skin, the pressure-resistant buoyancy layer, and the second skin are stacked in sequence. At the same time, the first skin, the pressure-resistant buoyancy layer, and the second skin are laid using a dry method, that is, the laid first skin, the pressure-resistant buoyancy layer, and the second skin are not soaked in the adhesive resin. Finally, the adhesive resin is introduced into the first skin, the pressure-resistant buoyancy layer, and the second skin in the mold cavity using vacuum negative pressure, and a one-step molding process is performed for overall co-curing. This lightweight underwater submersible composite sandwich load-bearing structure shell is light in weight and has good overall structural load-bearing performance. The vacuum-assisted resin transfer molding process is used for overall, one-step molding, ensuring the reliability and thickness consistency of the bonding between the layers, meeting the structural strength and water-resistance requirements, and eliminating defects such as bubbles and delamination at the bonding interface of the first skin, the pressure-resistant buoyancy layer, and the second skin, greatly improving the service life, safety factor, and reliability of the load-bearing structure shell. A new submersible bearing structure shell has been formed that can meet a series of performance index requirements such as lightweight, structural bearing performance, and environmental adaptability. This bearing structure shell is an important supporting equipment that is indispensable for the upgrading of lightweight and high-performance deep-sea submersibles.

[0018] 2. In the lightweight underwater submersible composite sandwich load-bearing structure shell provided by the present invention, the channels comprise transverse and longitudinal channels, which are arranged crosswise. The arrangement of these channels facilitates the spread of adhesive resin through the channels of the pressure-resistant buoyancy layer to the entire pressure-resistant buoyancy layer. Furthermore, the channels are connected to the slot holes, allowing adhesive resin to flow vertically from the second skin to the first skin, gradually saturating the first skin, thereby impregnating the entire load-bearing structure shell with adhesive resin.

[0019] 3. In the lightweight underwater submersible composite sandwich load-bearing structural shell provided by the present invention, the thickness of the first surface aging-resistant layer, the first surface short fiber layer, the second surface aging-resistant layer, and the second surface short fiber layer is 0.15-0.2 mm. The shell is molded using a short fiber felt layer and epoxy resin. The first and second surface short fiber layers reduce porosity and provide a denser surface, preventing damage to the internal structural layers caused by deep-sea water pressure. Furthermore, they provide good adhesion transition between the first and second surface aging-resistant layers, as well as the subsequent outer surface isolation layer.

[0020] 4. The lightweight composite sandwich load-bearing structure shell of the underwater submersible provided by the present invention has a first surface aging-resistant layer and a second surface short fiber layer composed of an epoxy resin gel coat and 2% (mass fraction) fumed silica. This design ensures that the epoxy resin gel coat layer itself has excellent corrosion resistance, while the fumed silica is evenly mixed into the structure, creating a brick wall-like cross-section and forming a multi-layered glass flake insulation layer. This significantly improves the chemical corrosion resistance of the load-bearing structure shell, while the dense layer also has excellent hydrophobicity.

[0021] 5. The lightweight composite sandwich load-bearing structural shell of a submersible provided by the present invention comprises a resin-based reinforced fiber-reinforced composite laminate comprising multiple layers of carbon fiber multi-axial cloth, with adjacent layers of the carbon fiber multi-axial cloth arranged perpendicular to each other. The multiple layers of carbon fiber multi-axial cloth are laid at staggered angles to achieve greater in-plane shear strength, making the forces acting on the first and second skins more isotropic and more balanced. Furthermore, the multi-axial cloth facilitates the infiltration of the bonding resin into the first skin, the compressive buoyancy layer, and the second skin, compared to checkered woven cloth.

[0022] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic structural diagram of a composite sandwich load-bearing structure shell of a lightweight underwater submersible provided by the present invention;

[0025] Figure 2 A schematic structural diagram of the compressive buoyancy layer of the composite sandwich load-bearing structural shell of a lightweight underwater submersible provided by the present invention;

[0026] Figure 3 A schematic structural diagram of the auxiliary material layer of the composite sandwich load-bearing structural shell of a lightweight underwater submersible provided by the present invention;

[0027] Figure 4 A schematic structural diagram of the bonding resin flow channel of the composite sandwich load-bearing structural shell of the lightweight underwater submersible provided by the present invention;

[0028] Figure 5 Schematic diagram of the adhesive resin injection structure of the composite sandwich load-bearing structural shell of the lightweight underwater submersible provided by the present invention.

[0029] Description of reference numerals:

[0030] 1-first skin; 11-first surface aging-resistant layer; 12-first surface short fiber layer; 13-first surface structural layer; 2-compression buoyancy layer; 21-groove; 22-transverse groove body; 23-longitudinal groove body; 24-slot hole; 3-second skin; 31-second surface aging-resistant layer; 32-second surface short fiber layer; 33-second surface structural layer; 4-bonding resin flow channel; 41-injection port; 42-main channel; 43-branch channel; 5-vacuum negative pressure interface; 6-mold release layer; 7-first air guide layer; 8-first layer of sealing bag film; 9-second air guide layer; 10-second layer of sealing bag film; 101-sealing strip; 102-mold. DETAILED DESCRIPTION

[0031] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0032] In the description of the present disclosure, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely for the purpose of facilitating the description of the present disclosure and simplifying the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of the present disclosure, "plurality" means two or more, unless otherwise expressly and specifically defined.

[0033] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, removable, or integral connections; mechanical, electrical, or intercommunication connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0034] In this disclosure, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact via another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the first feature is at a lower level than the second feature.

[0035] The disclosure below provides many different embodiments or examples for realizing different structures of the present disclosure. In order to simplify the disclosure of the present disclosure, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present disclosure. In addition, the present disclosure may repeat reference numbers and / or reference letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0036] The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0037] See also Figures 1 to 5 As shown, the present invention provides a lightweight underwater submersible composite sandwich load-bearing structural shell, including: a first skin 1 and a pressure-resistant buoyancy layer 2, and a second skin 3 laid in sequence, the first skin 1 including a first surface aging-resistant layer 11 and a first surface short fiber layer 12, and a first surface structural layer 13; the second skin 3 including a second surface aging-resistant layer 31 and a second surface short fiber layer 32, and a second surface structural layer 33, the first surface structural layer 13 and the second surface structural layer 33 are close to the pressure-resistant buoyancy layer 2; grooves 21 are provided on the upper and lower surfaces of the pressure-resistant buoyancy layer 2, and slots 24 are provided along the thickness direction of the pressure-resistant buoyancy layer 2, and the slots 24 in the grooves 21 are filled with adhesive resin.

[0038] The first skin 1, the pressure-resistant buoyancy layer 2, and the second skin 3 are stacked in sequence. These layers are dry-laid, meaning they are not impregnated with adhesive resin. Finally, the adhesive resin is introduced into the mold cavity of the mold using vacuum negative pressure, and the entire structure is co-cured in a single-shot molding process. This lightweight underwater submersible composite sandwich load-bearing structure boasts a lightweight and high-performance overall structural load-bearing performance. The vacuum-assisted resin transfer molding process ensures reliable bonding and uniform thickness between the layers, ensuring structural strength and water resistance. This eliminates defects such as bubbles and delamination at the bonding interface between the first skin 1, the pressure-resistant buoyancy layer 2, and the second skin 3, significantly improving the service life, safety factor, and reliability of the load-bearing structure. A new submersible bearing structure shell has been formed that can meet a series of performance index requirements such as lightweight, structural bearing performance, and environmental adaptability. This bearing structure shell is an important supporting equipment that is indispensable for the upgrading of lightweight and high-performance deep-sea submersibles.

[0039] In some optional embodiments, the channel 21 includes a transverse channel 22 and a longitudinal channel 23, and the transverse channel 22 and the longitudinal channel 23 are arranged crosswise. The arrangement of the channel 21 facilitates the bonding resin to spread through the channel 21 of the pressure-resistant buoyancy layer 2 to the entire pressure-resistant buoyancy layer 2, and the channel 21 is connected to the slot 24, so that the bonding resin can flow vertically from the second skin 3 to the first skin 1, gradually saturating the first skin 1, thereby impregnating the entire load-bearing structural shell with the bonding resin.

[0040] In some optional embodiments, the first surface aging-resistant layer 11 and the second surface short fiber layer 32 are composed of an epoxy resin gel coat and 2% (mass fraction) fumed silica; and the thickness of the first surface aging-resistant layer 11 and the second surface aging-resistant layer 31 is 0.15-0.2 mm. The first surface aging-resistant layer 11 and the second surface aging-resistant layer 31 are fiber-free, resin-rich layers. This design ensures that the epoxy resin gel coat layer itself has excellent corrosion resistance, while the fumed silica uniformly mixed into the layer creates a cross-section similar to a brick wall structure, forming a multi-layer glass flake isolation layer, greatly improving the chemical corrosion resistance of the load-bearing structure shell. At the same time, this dense layer has excellent hydrophobicity.

[0041] The thickness of the first surface short fiber layer 12 and the second surface short fiber layer 32 is uniformly 0.15-0.2 mm, and they are formed by short fiber felt layer and epoxy resin. The first surface short fiber layer 12 and the second surface short fiber layer 32 can reduce the porosity of the molded surface and make it more dense, preventing the deep sea water pressure from damaging the internal structural layer, and at the same time have a good bonding transition effect on the first surface aging-resistant layer 11 and the second surface aging-resistant layer 31, as well as the subsequent outer surface isolation layer.

[0042] In some optional embodiments, the first and second surface structural layers 13 and 33 are resin-based reinforced fiber-reinforced composite laminates. These layers serve as the primary load-bearing layers and exhibit excellent corrosion resistance and mechanical properties. Their tensile strength and modulus are even higher than those of standard steel, yet their specific gravity is less than one-quarter that of steel. The resin-based reinforced fiber-reinforced composite laminates comprise multiple layers of multi-axial carbon fiber fabric, with adjacent layers arranged perpendicular to each other.

[0043] Specifically, multiple layers of the carbon fiber multi-axial cloth can be laid along the 0° and 90° staggered positions of the load-bearing structural shell.

[0044] Multiple layers of the carbon fiber multi-axial fabric can also be laid with staggered seams of ±45°. Laying multiple layers of carbon fiber multi-axial fabric at different staggered angles can achieve greater in-plane shear strength, making the forces acting on the first skin 1 and the second skin 3 more isotropic and more balanced. Furthermore, compared to checkered woven fabric, multi-axial fabric is more conducive to the infiltration of the bonding resin into the first skin 1, the compressive buoyancy layer 2, and the second skin 3.

[0045] In some optional embodiments, the thickness of each layer of the carbon fiber twill fabric is 0.2-0.6 mm.

[0046] The compressive buoyancy layer 2 is made of an epoxy resin-based glass microbead buoyancy material. The density of this material can be adjusted based on the buoyancy requirements of the underwater vehicle to meet the compressive and buoyancy requirements at different water depths. The buoyancy material is a solid, machinable material. Grooves 21 are machined into the upper and lower surfaces of the buoyancy material. The groove depth and width are determined based on the product structure and process requirements. Slots 24 are drilled through the thickness of the buoyancy material, connecting the grooves on the upper and lower surfaces. Such a design ensures that the grooves 21 processed on the surface of the buoyancy material provide the necessary means for the rapid flow and infiltration distance of the adhesive resin. The adhesive resin flows in the processed grooves 21 and then infiltrates the first skin 1 and the human skin attached to the upper surface of the pressure-resistant buoyancy layer 2. The penetrating slots 24 can ensure the synchronization of the infiltration of the fiber-reinforced material on the upper and lower surfaces of the pressure-resistant buoyancy layer 2. At the same time, resin glue columns are formed in each slot 24 in the pressure-resistant buoyancy layer 2, thereby further improving the bonding strength between the first skin 1 and the pressure-resistant buoyancy layer 2, and the second skin 3.

[0047] The present invention also provides an integrated molding process for a lightweight underwater submersible composite material sandwich load-bearing structure shell, comprising the following steps:

[0048] S1. Provide a mold that meets the requirements based on the shape and structure of the load-bearing structural shell. The mold is provided with multiple bonding resin injection ports and vacuum negative pressure interfaces 5. The mold has certain structural rigidity, precise size and shape, perfect sealing, demoldability and resistance to thermal deformation required for product molding.

[0049] S2, using a wool roller to roll-coat a layer of epoxy resin gel coat and 2% (mass fraction) fumed silica on the mold to form a first surface aging-resistant layer 11. The amount is accurately measured according to the design requirements. After the roll coating is completed, it is cured at room temperature. The thickness of the composite material layer is 0.1 to 0.15 mm.

[0050] S3, evenly spray an appropriate amount of fiber fixing glue on the cured first surface aging-resistant layer 11, and lay the first surface short fiber layer 12, and then lay the first surface structural layer 13 on the first surface short fiber layer 12, the first layer of carbon fiber multi-axial cloth of the first surface short fiber layer 12 is laid in a direction consistent with the axial direction of the load-bearing structural shell, and each width of carbon fiber multi-axial cloth is butt-laid, when the carbon fiber multi-axial cloth covers the entire mold surface, spray an appropriate amount of fiber fixing glue on the first layer of carbon fiber multi-axial cloth, and lay the second layer of carbon fiber multi-axial cloth in a 45° direction of the seam with the first layer of carbon fiber multi-axial cloth, and subsequently lay the remaining -45° and 90° carbon fiber multi-axial cloths in this way; such a design allows the carbon fiber multi-axial cloth to be staggered at different angles, which can obtain a greater in-plane shear strength, so that the various forces of the first skin 1 tend to be isotropic and the load-bearing is more balanced.

[0051] S4, the compressive buoyancy layer 2 is formed by splicing multiple pieces together as a whole. When laying, the splicing gap is controlled and is required to be less than 0.5 mm. The grooves 21 on the upper and lower surfaces of each compressive buoyancy layer 2 are aligned one by one to ensure that the adhesive resin flows smoothly in the grooves 21 of the compressive buoyancy layer 2.

[0052] S5, the second surface structure layer 33 is laid on the compressive buoyancy layer 2, and the first layer of carbon fiber multi-axial cloth of the second surface structure is laid on the compressive buoyancy layer 2 along the direction consistent with the axial direction of the load-bearing structure shell, and each width of carbon fiber multi-axial cloth is laid butt-jointed. When the carbon fiber multi-axial cloth covers the entire mold surface, an appropriate amount of fiber fixing glue is sprayed on the first layer of carbon fiber multi-axial cloth, and the second layer of carbon fiber multi-axial cloth is laid along the 45° direction of the seam with the first layer of carbon fiber multi-axial cloth, and the remaining -45° and 90° carbon fiber multi-axial cloths are subsequently laid in this way; such a design allows the carbon fiber multi-axial cloth to be laid at different angles, which can obtain a greater in-plane shear strength, so that the various forces on the second skin 3 tend to be isotropic and the load-bearing is more balanced.

[0053] S6, spraying an appropriate amount of fiber fixing glue evenly on the second surface structure, laying a second short fiber layer, and using a wool roller to roll-coat a layer of epoxy resin gel coat and 2% (mass fraction) fumed silica on the second short fiber layer to form a second surface aging-resistant layer 31. After the roll-coating is completed, it is allowed to cure at room temperature. The thickness of the composite material layer is 0.1 to 0.15 mm;

[0054] S7, laying auxiliary material layers in sequence on the surface of the first skin 1, the auxiliary material layers including a release layer 6, a first air guide layer 7, an adhesive resin flow channel 4, a first sealing bag film 8, a second air guide layer 9, and a second sealing bag film 10;

[0055] S8, the epoxy resin and curing agent are mixed and stirred to form a bonding resin, the bonding resin gel time is 4 to 6 hours, and the bonding resin viscosity is 0.15 to 0.25 Pa·s; the pipe of the bonding resin flow channel 4 connected to the mold at one end is connected to the bonding resin injection end, and the vacuum negative pressure pipe is connected to the bonding resin discharge port of the mold. The vacuum pressure in the first layer of sealing bag film 8 needs to reach -0.07MPa to -0.08MPa, and the vacuum pressure in the second layer of sealing bag film 10 needs to reach -0.09MPa to -0.1MPa. The bonding resin is introduced into the mold cavity of the mold under the action of the positive pressure of the injection equipment and the vacuum negative pressure. The bonding resin first flows through the auxiliary material layer. After the auxiliary material layer is soaked with the bonding resin, the second skin 3 is soaked, and then the bonding resin passes through the pressure-resistant buoyancy layer 2 The adhesive resin flows into the first skin 1 through the grooves 21 and the slots 24 in the pressure-resistant buoyancy layer 2, and gradually permeates the first skin 1. When the adhesive resin overflows from each adhesive resin outlet, it indicates that the adhesive resin has completely permeated the auxiliary material layer and the second skin 3, the pressure-resistant buoyancy layer 2, and the first skin 1. Then, the adhesive resin injection can be stopped. However, the vacuum pressure at the vacuum negative pressure end must be maintained until the bond is completely cured, and then the vacuum negative pressure can be stopped.

[0056] S9, heating and curing the load-bearing structure shell in the mold state.

[0057] The release layer 6 is made of polyester fiber woven cloth. This design allows the layer of cloth to be peeled off from the product after the bearing structure shell is formed, forming a matte surface with uniform texture on the inner surface and no glue edges or burrs.

[0058] The first air guide layer 7 and the second air guide layer 9 are both made of 2mm thick polyester fiber fluffy fabric. Such a design makes the fluffy fabric conducive to forming an air guide channel, so that the vacuum pressure is evenly and quickly transmitted to the surface of the product.

[0059] The bonding resin flow channel 4 includes three injection ports 41, which are spaced apart along the extension direction of the bearing structure shell. At the same time, the bonding resin flow channel also includes a main channel 42 and a branch channel 43. The main channel 42 is arranged to coincide with the transverse groove body 22, and the branch channel 43 is arranged to coincide with the longitudinal groove body 23. Among them, the bonding resin inlet and outlet ports are simulated and designed by bonding resin diversion simulation software and verified by experiments, and the vacuum bonding resin introduction process is implemented for products that fully meet the size, shape and internal structure design.

[0060] The bonding resin flow channel 4 is constructed from nylon spiral tubing, providing a relatively large cross-sectional channel for the bonding resin. This design allows the bonding resin to flow quickly and diffuse rapidly within the seams of the spiral tubing, eliminating the white spots that can occur when the bonding resin is not fully infiltrated due to improper flow channel design. This significantly improves the resin infiltration efficiency and fiber layup quality.

[0061] The first layer of sealing bag film 8 is made of nylon polyester material. The first layer of sealing bag film 8, the sealing strip 102 and the mold form a sealed space, and the sealed space is vacuumed and pressurized so that the above-mentioned laid materials fit in place under atmospheric pressure. The pressure value in the bag film should meet the design requirements to meet the requirements of resin introduction speed and distance.

[0062] The air guide layer is made of a glass fiber surface felt with a grammage of less than 30g / ㎡. This design not only provides good air conduction, but also provides good transparency due to the thin wire mesh structure, making it easy to observe the internal adhesive resin penetration through the first and second sealing bag films 8 and 10.

[0063] The second layer of sealing film 10 is made of nylon polyester. It, the sealing tape, and the first layer of sealing film 8 form a sealed space, which is then vacuumed and pressurized. This design allows the second layer of sealing film 10 to serve as a leak-proof backup for the first layer of sealing film 8. Crucially, after the adhesive resin has completely soaked the product layer within the first layer of film, atmospheric pressure decreases, increasing the adhesive content and thickness of the product. No resin enters the second layer of sealing film 10, allowing the vacuum pressure to be maintained continuously, ensuring product thickness.

[0064] It is made by an integrated molding process, in which all the first skin 1, the pressure-resistant buoyancy layer 2, and the second skin 3 are laid out in a dry form, and finally the bonding resin is introduced into the first skin 1, the pressure-resistant buoyancy layer 2, and the second skin 3. The laying of the first skin 1, the pressure-resistant buoyancy layer 2, and the second skin 3 is no longer affected by the curing time of the bonding resin, and precise laying and shaping can be performed, which greatly improves the uniformity of the first skin 1, the pressure-resistant buoyancy layer 2, and the second skin 3; the bonding resin is bonded to the first skin 1 and the pressure-resistant buoyancy layer 2 under the positive pressure of the equipment and the vacuum negative pressure in the mold cavity. 2. Diffusion impregnation is carried out in the second skin 3, and the glue content in the fiber layer is as low as about 35%. The resin consumption of the load-bearing structure shell is reduced by 1 / 4. At the same time, the buoyancy material is also bonded and co-cured in one time, eliminating the adhesive layer for later bonding, reducing the total weight by 1 / 5, and making a great contribution to the lightweight design of the equipment; ensuring the reliability and thickness uniformity of the bonding between the first skin 1 and the compressive buoyancy layer 2, and the second skin 3, eliminating the defect problem of bulging and delamination on the surface of the load-bearing structure shell, and greatly improving the service life, safety factor and reliability of the load-bearing structure shell.

[0065] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An integrated molding process for a lightweight underwater submersible composite sandwich load-bearing structure shell, characterized in that: The housing includes: A first skin (1), a pressure-resistant buoyancy layer (2), and a second skin (3) are laid in sequence, wherein the first skin (1) comprises a first surface aging-resistant layer (11), a first surface short fiber layer (12), and a first surface structural layer (13); The second skin (3) comprises a second surface aging-resistant layer (31), a second surface short fiber layer (32), and a second surface structural layer (33), wherein the first surface structural layer (13) and the second surface structural layer (33) are close to the compressive buoyancy layer (2); Grooves (21) are provided on the upper and lower surfaces of the pressure-resistant buoyancy layer (2), and slot holes (24) are provided along the thickness direction of the pressure-resistant buoyancy layer (2), and the slot holes (24) in the grooves (21) are filled with adhesive resin; The channel (21) comprises a transverse channel body (22) and a longitudinal channel body (23), wherein the transverse channel body (22) and the longitudinal channel body (23) are arranged crosswise; The first surface aging-resistant layer (11) and the second surface aging-resistant layer (31) are composed of epoxy resin gel coat and 2% (mass fraction) fumed silica; The integrated molding process comprises the following steps: S1, providing a mold that meets the requirements according to the shape and structure of the load-bearing structure shell, and the mold is provided with multiple bonding resin injection ports and vacuum negative pressure interfaces (5); S2, using a wool roller to roll a layer of epoxy resin gel coat and 2% (mass fraction) fumed silica on the mold to form a first surface aging-resistant layer (11), and after the roll coating is completed, it is cured at room temperature. The thickness of the first surface aging-resistant layer (11) is 0.15-0.2 mm; S3, spraying an appropriate amount of fiber fixing glue evenly on the solidified first surface aging-resistant layer (11), and laying the first surface short fiber layer (12), and then laying the first surface structural layer (13) on the first surface short fiber layer (12), the first layer of carbon fiber multi-axial cloth of the first surface structural layer (13) is laid along the direction consistent with the axial direction of the load-bearing structural shell, and each width of carbon fiber multi-axial cloth is butt-laid, when the carbon fiber multi-axial cloth covers the entire mold surface, spraying an appropriate amount of fiber fixing glue on the first layer of carbon fiber multi-axial cloth, laying the second layer of carbon fiber multi-axial cloth along the 45° direction of the seam with the first layer of carbon fiber multi-axial cloth, and subsequently laying the remaining -45° and 90° carbon fiber multi-axial cloths in this way; S4, the compression buoyancy layer (2) is a multi-piece splicing unit, and the splicing gap is controlled during laying, and the gap is required to be less than 0.5 mm, and the grooves (21) on the upper and lower surfaces of each compression buoyancy layer (2) are aligned one by one; S5, the second surface structure layer (33) is laid on the compressive buoyancy layer (2), the first layer of carbon fiber multi-axial cloth of the second surface structure is laid on the compressive buoyancy layer (2) along the direction consistent with the axial direction of the load-bearing structure shell, and each width of carbon fiber multi-axial cloth is laid in a butt-jointed manner. After the carbon fiber multi-axial cloth covers the entire mold surface, an appropriate amount of fiber fixing glue is sprayed on the first layer of carbon fiber multi-axial cloth, and the second layer of carbon fiber multi-axial cloth is laid along the 45° direction of the seam with the first layer of carbon fiber multi-axial cloth, and the remaining -45° and 90° carbon fiber multi-axial cloths are subsequently laid in this manner; S6, spraying an appropriate amount of fiber fixing glue evenly on the second surface structure, and laying a second short fiber layer, using a wool roller to roll a layer of epoxy resin gel coat and 2% (mass fraction) fumed silica on the second short fiber layer to form a second surface aging-resistant layer (31), and after the rolling is completed, it is cured at room temperature. The thickness of the second surface aging-resistant layer (31) is 0.15~0.2mm; S7, laying auxiliary material layers in sequence on the surface of the second skin (3), the auxiliary material layers including a release layer (6), a first air guide layer (7), an adhesive resin flow channel, a first sealing bag film (8), a second air guide layer (9), and a second sealing bag film (10); S8, mixing the epoxy resin and the curing agent to form a bonding resin, wherein the bonding resin gel time is 4 to 6 hours and the bonding resin viscosity is 0.15 to 0.25 Pa·s; connecting the bonding resin flow channel of the mold at one end to the bonding resin injection end, and connecting the vacuum negative pressure pipeline to the bonding resin discharge port of the mold, the vacuum pressure in the first layer of the sealing bag film (8) needs to reach -0.07MPa to -0.08MPa, and the vacuum pressure in the second layer of the sealing bag film (10) needs to reach -0.09MPa to -0.1MPa, and the bonding resin is introduced into the mold cavity of the mold under the action of the positive pressure of the injection equipment and the vacuum negative pressure, and the bonding resin first flows through the auxiliary material layer, and after the auxiliary material layer is soaked by the bonding resin, the second skin (3) is soaked, and then the bonding resin flows into the first skin (1) through the groove (21) of the pressure-resistant buoyancy layer (2) and the groove hole (24) in the pressure-resistant buoyancy layer (2), and gradually soaks the first skin (1); When the adhesive resin overflows from each adhesive resin discharge port, it indicates that the adhesive resin has completely impregnated the auxiliary material layer and the second skin (3), the pressure-resistant buoyancy layer (2), and the first skin (1), and the adhesive resin injection can be stopped. However, the vacuum pressure at the vacuum negative pressure end must be maintained until the adhesive is completely cured, and then the vacuum negative pressure can be stopped. S9, heating and curing the load-bearing structure shell in the mold state.

2. The integrated molding process of the composite sandwich load-bearing structure shell of a lightweight underwater submersible according to claim 1 is characterized in that: The thickness of the first surface short fiber layer (12) and the second surface short fiber layer (32) is 0.15-0.2 mm.

3. The integrated molding process of the composite sandwich load-bearing structure shell of a lightweight underwater submersible according to any one of claim 1, characterized in that: The thickness of each layer of the carbon fiber multi-axial cloth is 0.2 to 0.6 mm.

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